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Interfit S1 AC/DC HSS TTL Monolight

Interfit S1 AC/DC HSS TTL Monolight
Key Features
  • 1 x S1 500Ws Flash Head
  • 1 x Li-Ion Battery and Charger
  • 1 x Bowens-Mount Reflector
  • Optional Canon/Nikon/Sony Transmitter
With the introduction of the of the S1 AC/DC HSS TTL Monolight from Interfit, the company elevates its place in the ever-widening group of manufacturers producing TTL monolights.
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Interfit S1 Overview

  • 1Description
  • 2Compatibility and Firmware Updates
  • 3Complete Package
  • 4S1N TTL Remote
  • 5Power Supply
  • 6Shooting Modes
  • 7Manual Mode and High-Speed Sync
  • 8IGBT

With the introduction of the of the S1 AC/DC HSS TTL Monolight from Interfit, the company elevates its place in the ever-widening group of manufacturers producing TTL monolights.

The flash head is powered by an internal, removable 4500mAh lithium-ion battery that fits inside the head's housing. It has a 350 full-power flash capacity and can also run on an optional AC adapter while your battery is charging. It's controllable wirelessly at distances up to 328'.

The S1 has 3 shooting modes: Wireless TTL for Canon, Nikon, or Sony; Manual Mode; and High-Speed Sync. Wireless requires purchase of a Nikon, Canon, or Sony dedicated transmitter, but once that's done, you can basically treat these studio strobe units as you would your on-camera flash. In TTL, the camera's flash technology takes stock of the scene and automatically adjusts the power from 1.9 to 500Ws across a 9-stop range. If you want to fine tune your exposure, there's +/-3 stops exposure compensation adjustable in 1/3 stops.

Traditional manual mode is available for those who want complete control. Manual mode (1/250 sec) is also how you access HSS (High-Speed Sync). This mode uses the flash's top 3 power levels (from 125 to 500Ws) to allow you to access sync speeds as short as 1/8000. HSS presents a new world of exposure possibilities whether you're trying to overpower the sun, control the background's brightness, or use wider apertures.

The S1 recycles to full power in 3 seconds and a fraction of that time at reduced power levels. Thanks to the incorporation of IGBT technology, the flash can also reach flash durations as short as 1/11,000 sec for the ultimate in stop-action while still maintaining a steady 5700K color temperature.

The S1 ships as a complete system including a 350-shot lithium-ion battery with a charger that powers it up in about 3 hours. Since the S1 is AC/DC, it can also be plugged into a wall outlet for use via a separately-purchased AC adapter regardless of its voltage while the battery is charging. The S1 also includes a 7" Bowens S-Type reflector, and a mini USB cable.

Compatibility and Firmware Updates
In order to ensure maximum compatibility with your system, Interfit offers firmware updates for download on their website. These updates can be easily installed by the user by connecting the monolight to their computer over USB.
Complete Package
500Ws monolight with High-Speed Sync, TTL for Canon and Nikon, IGBT technology, and a lithium-ion battery and charger in one complete package.
S1N TTL Remote
The S1's TTL remotes give the users direct control over any S1 light in any shooting mode from the camera position. This camera-mounted transmitter is available for both Canon, Nikon and Sony cameras. Having three individual groups gives users the freedom to control lights individually to create dynamic lighting ratios with a working range of up to 300' / 100m.
Power Supply
Each Interfit S1 comes standard with both battery and charger . The interchangeable 4500mAh Li-ion battery provides up to 350 full power flashes in Manual and TTL modes and over 400 full-power flashes in High-Speed Sync mode. This wire-free power source gives photographers the freedom and mobility to venture out from the studio and rapidly set up and reposition lights on location. For traditional studio work, the there is an optional AC power adapter available. This multi-voltage (100-240V) adapter can be used anywhere in the world and lets photographers continue to shoot while their battery is charging.
Shooting Modes
The S1 has three different shooting modes, each to serve a different purpose and shooting style. Interfit's S1 Remote for Canon, Nikon or Sony enables photographers to take advantage of their camera's TTL system just like they would with a speedlight. This automated light output uses the S1's entire 9-stop power range (500W - 1.9Ws), is automatically calculated in 1/10th stop increments, and allows for +/-3 stops of exposure compensation.
Manual Mode and High-Speed Sync
For those that prefer to have complete control of their light and have time for fine-tuned adjustments, the S1 can be used in the traditional manual mode. Manual shooting mode also utilizes the entire 9-stop power range, controllable in 1/10th stop increments. While in 1/250 sec. manual mode, users can access the S1's High Speed Sync mode, reaching shutter speeds up to 1/8000th of a second. High-Speed Sync mode utilizes the top 3 stops in the power range (500 - 125Ws) and is manually adjustable in 1/3-stop increments.
Utilizing IGBT technology, the S1 is able to offer short flash durations while maintaining color accuracy throughout the power range. Flash duration ranges from 1/500 at full power, to 1/11,000 at minimum power. While shortening the flash duration, Interfit was also able to improve color accuracy, giving the S1 a consistent 5700K (+/-100K) color temperature throughout the entire power range

Interfit S1 Specs

Flash Head
Maximum Power500 Ws
Power Control9 Stops in 1/10-Stop Increments
Guide Number160' / 48.7 m at 9.8' / 3 m, ISO100
Flash Duration1/11,000 to 1/500 Sec
Recycle Time3 Sec (Full Power)
Color Temperature5700K +/- 100K
Accessory Fitting TypeBowens S Type
Modeling Light
Wattage10 W
Control ModesFull On, Off
Sync TypeCable, Infrared, Optical, Radio
Built-In Wireless ReceiverYes
Sync Speed1/1/250 Sec (Normal)
1/1/8000 Sec (High-Speed)
Wireless Frequency Bands2.4 GHz
Wireless Range328' / 100 m (Radio)
AC Input Power100 to 240 VAC, 50 / 60 Hz
Battery ChemistryLithium-Ion
Capacity (mAh)4500 mAh
Flashes Per Charge350 Flashes (Full Power)
Recharge Time3 Hours
Auto DumpYes
Fan CooledYes
Dimensionsø: 5.1 x L: 13.4" / ø: 13.0 x L: 34.0 cm, Including Handle
Weight6.3 lb / 2.85 kg, Including Battery
Packaging Info
Package Weight10 lb
Box Dimensions (LxWxH)21 x 11 x 10.5"

Interfit S1 Reviews


By Angel
Rated 4 out of 5
Date: 2022-04-24

GOOD! BUT NOT PARTS AVAILABLE ANY LONGER!!! I believe is a scam to sell a product form which you don't longer have part available including INTERFIT, the have nothing available? What is going on, you are not even advising customer the risk there are taking when buying Interfit! all parts are discontinued!!! that's not nice to invest money in the product than in less than a year they have not replacements available, never buy cheap! cheap is cheap!!!

New tech is not always better.

By Edmund
Rated 2 out of 5
Date: 2022-02-28

I have been using interfit lights for nearly 15 years. The ONLY reason I replaced them is because the plastic housings got sticky. I decided I would stick with a brand I knew. I guess I guessed wrong. I am not too happy. The new lights are more expensive (I understand everything goes up - but I waited 8 months to get them). They come with less than the original kits (No stands). The LED modeling lights are weak, (Very dim) even in my dark studio. My studio space is about 10 x 10, I doubt they would throw enough light to see what you need to see in a larger studio. They don't come as electrical units and are battery powered. You have to spend over $200 each to get the AC adapters. I found out my old interfit remote works, so I didn't have to spend more money on the TTL adapter (I don't need ttl & actually Interfit told me the first time I tried to order them last year they would give me a free TTL remote, and that offer dried up - they won't even respond to me now). The battery life indicator is on the top of the battery facing upwards. You have to lower the light to see how much battery you have left or wait for it to die. The instruction manual is one side of a stock sheet and it got punched through & torn by the lights due to rough handling. The instruction sheet says charge the batteries for 3 hours. It took three days. The readouts on the back of the lights don't seem to correspond to the dialed in f-Stop. I haven't put more effort into checking that yet. I haven't given them a proper shake down so I am not sure about the true functions, but they seem be much less powerful than the interfit monolights I replaced.

Love these still

By suzanne
Rated 5 out of 5
Date: 2021-11-22

I've had my Interfit S1 lights for a while now and this past Fall, picked up another two to round out my set. I'm eagerly waiting for them to come back into the shop (knowing they're dealing with chip shortages etc.). They've been absolute tanks and worked beautifully on set. They do single shot HSS and are 100% wireless, making them excellent for scenarios when you need to be super nimble, but also the long battery life makes them great for long days on set.

Versatile, easy to work with, mobile, and long battery life

By suzanne
Rated 5 out of 5
Date: 2021-09-05

I picked one of these up back in 2019 out of curiosity. It wasn't long before it became my go-to light and was joined by three others. The battery life is spectacular. I can bring these to set, and fire away all day without having to swap (nearly always the case). The batteries also charge quickly, so if you have a backup battery, you'll be in great shape to keep firing away with confidence. The triggers are equally frugal with battery use if not more. I love that they don't contribute to the cables, snaking along the floor or draped overhead. They keep the set tidy, do their job, and do it really well at that. In contrast, I have Profoto D2s as well as backup lights in case anything goes haywire, but haven't had to break those out. In contrast the Profoto trigger eats batteries and I know I'll need to change those at least once during a shoot. Not awesome if you have your camera up high and out of reach. For the money, these are 100% my go-to lights. They work with me on set all day at commercial and editorial shoots and just keep marching along. 100% recommended.

Versatility at a Great Price

By William
Rated 5 out of 5
Date: 2021-07-29

This is my first battery operated strobe and it has made an amazing first impression! The 10 stop power range provides everything I need indoors and outdoors (especially with the option of High Speed Sync). The only stipulation is that if you want the HSS, you need the Interfit wireless transmitter; honestly worth the extra $100. I have yet to take this light on a shoot and run out of battery power! Some days will have two shoots with different uses of flash and this baby will last all day! The frosted cover is also a great protector/diffuser for the strobe bulb. I have used Paul C. Buff lights for years and this is the first light to make me consider changing my brand loyalties! This light has yet to fail me on any shoot where I've needed the flexible reliability of a battery powered strobe. Highly, highly recommended!

Very usable portable flash

By Lou
Rated 4 out of 5
Date: 2021-06-15

Just received my Interfit S1 and have only enough time to do a test run. Once the remote and flash paired, it was a cinch to shoot from from my Z6. It even works when mounted atop my Pocket Wizard Mini TT1. I will be doing on site portraits using this as my main light and when needed, my Quantum Q4D for fill.

No customer support

By Karen
Rated 1 out of 5
Date: 2022-04-05

This company did not respond to 3 emails and a phone call. One of my lighting units stopped operating properly. I do not recommend purchasing from a company with non-existent product support.

Are these durable? Not so much....

By John
Rated 2 out of 5
Date: 2022-03-04

BUYER BEWARE. My studio is a portrait studio and we have ordered 8 Interfits of these same units. The functionality is great. The reliability is not so good. Construction is a 4 at best out of 10. Finding an outlet to repair, non-existent. This is using it until it does not work and throw it away. We have moved onto another brand to try.

See any errors on this page? Let us know


How do I get this to work with my Nikon D850?

How do I get this to work with my Nikon D850?
Asked by: Michael
You need to purchase the Nikon remote transmitter for the camera hotshot (B&H # INRS1N MFR # INTR1N)
Answered by: Brian
Date published: 2020-11-02

does this light fit on a 5/8" boom mount?

does this light fit on a 5/8" boom mount?
Asked by: Jeffrey
Yes. The mount is a standard 5/8 socket
Answered by: Adrian
Date published: 2021-01-15

Can I use my pocket wizard transceivers and shoot ...

Can I use my pocket wizard transceivers and shoot on manual with this or the only way to shoot wireless is with the interfit optional transmitter?
Asked by: Jorge
As the Interfit S1 AC/DC HSS TTL Monolight has a 1/8" (3.5 mm) miniphone headphone input terminal built into the light fixture, yes, you may either use PocketWizard transceivers with a 1/8" (3.5 mm) sync cable or the Interfit S1 Manual Remote for all Cameras to wirelessly trigger the monolight.
Answered by: Manzell
Date published: 2022-08-04

Does the old remote for Nikon That came with the ...

Does the old remote for Nikon That came with the s1 work with the new s1n
Asked by: Robert
Yes it does. There is no difference between the S1 and the S1N with regards to function. The only difference is that the S1N does not include the AC Power Pack. The light still has the ability to run off AC power, but the AC Power Pack is now sold separately.
Answered by: Interfit Product Expert
Date published: 2019-08-28

I have a Nikonn 7200, using the Nikon remote and ...

I have a Nikonn 7200, using the Nikon remote and all the settings are synced, but the strobes do not fire. What am I missing or doing wrong?
Asked by: Paul
You should be contacting interfit customer support
Answered by: Adrian
Date published: 2020-07-15

Does it work with pentax k1 camera?

Does it work with pentax k1 camera?
Asked by: Jorge
The Interfit S1 AC/DC HSS TTL Monolight will work with Pentax K! in manual modes
Answered by: Shalom
Date published: 2020-06-25

Is the flash tube user replaceable?

Is the flash tube user replaceable?
Asked by: David
Yes, the flashtube is user replaceable. That would be the Interfit Flash Tube for S1 Monolight, B&H # INSINTS1500F.
Answered by: Kirk
Date published: 2019-11-06

How can I shoot this unit with my canon and can I ...

How can I shoot this unit with my canon and can I use my YN622C transmitter?
Asked by: Santiago
You can use the Interfit transmitter The YN622C would not be advisable. You would need a receiver and you could only do manual with out any ability to adjust anything from the remote..
Answered by: Reuben
Date published: 2019-08-29
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